Intraoral Scanner Optical Axis Angles for Ghost Image Elimination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Intraoral scanners experience light-receiving noise and ghost images due to the reflection of scanning light through polarizers or transparent protection sheets, leading to distortion or failure in 3D tooth model formation.
Innovation Solution
The intraoral scanner design includes a light source, reflection plate, and receiver, where the projection optical axis forms a first oblique angle with the receiver and a second oblique angle with the transparent plate, ensuring that the reflection angle range falls outside the receiving angle range, preventing light noise and ghost images by adjusting the inclination of the transparent plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polarizer or transparent protection sheet is disposed between the light source and the reflection plate, then the scanning light can be protected and transmitted, but light-receiving noise and ghost images are generated due to reflection
Solution Approach 1:
The patent applies asymmetry by setting the projection optical axis to form a first oblique angle with the receiving optical axis, rather than using a symmetric perpendicular arrangement. This asymmetric configuration ensures that reflected light from the polarizer or protection sheet falls outside the receiver's acceptance cone, eliminating ghost images while maintaining light transmission functionality.
Solution Approach 2:
The patent introduces a dimensional solution by adjusting the angular relationship between optical axes from a traditional perpendicular arrangement to an oblique angle configuration. This dimensional change in optical path geometry redirects reflected light away from the receiver's detection path, solving the noise problem while preserving the protective function of the transparent components.
2Device complexity
If the projection optical axis is perpendicular to the receiving optical axis, then the structure is simple, but reflection causes light to incident back to the receiver generating noise
Solution Approach 1:
The patent resolves the contradiction by introducing asymmetric oblique angles between the projection and receiving optical axes. This asymmetric configuration is slightly more complex than a perpendicular arrangement but effectively redirects reflected light away from the receiver, eliminating noise while maintaining structural simplicity.
Solution Approach 2:
The patent converts the harmful reflection effect into a beneficial outcome by deliberately designing the oblique angle configuration. The reflection that would normally cause noise is instead harnessed to redirect light away from the receiver's detection path, transforming a harmful phenomenon into a useful design feature for noise elimination.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively reduces light-receiving noise and ghost images, improving the accuracy and quality of 3D tooth model identification and combination, ensuring successful image processing for dental applications.
Implementation Method 1
utilizing a reflection plate to reflect the scanning light to pass through a light exit opening of the intraoral scanner
Implementation Method 2
The projection optical axis forms a second oblique angle with a norm of the transparent plate to make a reflection angle range of light reflected by the transparent plate fall outside the receiving angle range
Data Source
AI summary
An intraoral scanner includes a casing, a light source disposed in the casing, a reflection plate obliquely disposed in the casing for reflecting light of the light source to an object to be scanned through an opening of the casing, a transparent plate, and a receiver adjacent to the light source. A projection optical axis of the light source forms a first oblique angle with a receiving optical axis of the receiver. The receiver receives light after being incident to the object to be scanned and then reflected to the receiver by the reflection plate. The transparent plate is disposed between the light source and the reflection plate or covers the opening. The projection optical axis forms a second oblique angle with a norm of the transparent plate to make a reflection angle range of light reflected by the transparent plate fall outside a receiving angel range of the receiver.